Paper cutting device and printer having a paper cutting device

Abstract

A first movable blade and a second movable blade cooperate as part of a cutter drive mechanism to cut roll paper in conjunction with a fixed blade. A gear train 132 has a first gear 141 that rotates when drive power from the cutter motor 131 is input thereto, and a second gear 142 to which rotation of the first gear 141 is transferred, causing the second gear 142 to turn. A first eccentric pin 151 engaging the first movable blade 81 is disposed at an eccentric position to the first gear 141, and a second eccentric pin 152 engaging the second movable blade 82 is disposed at an eccentric position to the second gear 142. The first movable blade 81 has a first guide channel 115 regulating the cutting operation of the first movable blade 81 on the first blade point 114 side, and the first guide channel 115 and the first eccentric pin 151 together render a first opposing cam 161. The second movable blade 82 has a second guide channel 125 regulating the cutting operation of the second movable blade 82 on the second blade point 124 side, and the second guide channel 125 and the second eccentric pin 152 together render a second opposing cam 162.

What is claimed is: 
     
       1. A paper cutting device comprising:
 a fixed blade having a cutting edge; 
 a first movable blade, having a first cutting edge terminating in a first 
 cutting point and a second movable blade, having a second cutting edge terminating in a second cutting point, disposed for relative movement against the fixed blade with the blade points facing the fixed blade in mutual opposition, the first movable blade having a first guide channel and the second movable blade having a second guide channel; 
 a first support stud for pivotably supporting rotational movement of the first movable blade; 
 a second support stud for pivotally supporting rotational movement of the second movable blade independent of the first movable blade; 
 a cutter drive mechanism for driving the first movable blade and the second movable blade to cause a cooperative cutting operation; 
 wherein the cutter drive mechanism includes
 a cutter motor; 
 a gear train including a first gear that is rotationally driven by said cutter motor, and a second gear that is rotationally driven in response to rotation of the first gear; 
 a first eccentric pin that is disposed to an eccentric position on the first gear and engages the first movable blade; and 
 a second eccentric that is disposed to an eccentric position on the second gear and engages the second movable blade; 
 
 a first cam formed by the first guide channel and the first eccentric pin for regulating the cutting operation of the first movable blade; and 
 a second cam formed by the second guide channel and the second eccentric pin for regulating the cutting operation of the second movable blade; 
 wherein the first movable blade and the second movable blade are (i) configured for movement independent of each other, and (ii) disposed so that the paths of the first cutting point and the second cutting point at least partially overlap during the cutting operation; and 
 wherein the first guide channel or the second guide channel has a bend at approximately a middle portion thereof. 
 
     
     
       2. The paper cutting device described in  claim 1 , wherein the gear train further comprises:
 an input gear that is affixed to the drive shaft of the cutter motor and meshes with the first gear; and 
 a middle gear that is affixed coaxially to the first gear, meshes with the second gear, and has the same number of teeth as the second gear. 
 
     
     
       3. The paper cutting device described in  claim 1 , wherein the gear train further comprises:
 an input gear that is affixed to the drive shaft of the cutter motor and meshes with the first gear; and 
 the second gear meshes with the first gear and has the same number of teeth as the first gear. 
 
     
     
       4. The paper cutting device described in  claim 1 , wherein:
 the cam profile of the first guide channel and the cam profile of the second guide channel are shaped such that the timing of the movement of the first movable blade is offset from the timing of the movement of the second movable blade so that the first cutting point and the second cutting point do not interfere with each other during the cutting operation. 
 
     
     
       5. The paper cutting device described in  claim 4 , wherein:
 the cam profile of the first guide channel and the cam profile of the second guide channel are shaped such that whichever one of either the first movable blade and the second movable blade that leads on the cutting stroke of the cutting operation will follow on the retraction stroke after cutting the paper. 
 
     
     
       6. The paper cutting device described in  claim 1 , wherein:
 the first and second cutting points move along radial paths in opposite directions with 
 the fixed blade disposed at a position in the paths of the first and second cutting points where the points do not overlap. 
 
     
     
       7. The paper cutting device described in  claim 1 , wherein:
 the first and second cutting points move along radial paths in opposite directions with the fixed blade disposed at a position in the paths of the first and second cutting points where the points overlap. 
 
     
     
       8. The paper cutting device described in  claim 1 , further comprising:
 a fixed blade frame for supporting the fixed blade; and 
 a movable blade frame connected to the first support stud and to the second support stud for supporting the first movable blade and the second movable blade at positions separated from the cutting edge of the fixed blade; and 
 wherein a paper transportation path is located above the cutting edge of the fixed blade and provides access thereto for changing paper by moving the fixed blade frame and the movable blade frame relative to each other. 
 
     
     
       9. The paper cutting device described in  claim 8 , wherein the fixed blade is disposed relative to the first movable blade and the second movable blade to form a cutting position based upon the contact relationship of the fixed blade and the movable blade frame. 
     
     
       10. The paper cutting device described in  claim 8 , wherein the fixed blade includes a pair of protrusions formed at opposite ends of the fixed blade in alignment with the cutting edge for engaging the movable blade frame at two places, and a pin protruding from the fixed blade opposite the cutting edge. 
     
     
       11. A printing apparatus including a paper cutting device comprising:
 a fixed blade having a cutting edge; 
 a first movable blade, having a first cutting edge terminating in a first cutting point and a second movable blade, having a second cutting edge terminating in a second cutting point, disposed for relative movement against the fixed blade with the blade points facing the fixed blade in mutual opposition with the first movable blade and the second movable blade disposed so that the paths of the first cutting point and the second cutting point at least partially overlap during the cutting operation, wherein the first moveable blade and the second moveable blade are configured for movement independent of each other, the first movable blade having a first guide channel and the second movable blade having a second guide channel; 
 a first support stud for pivotally supporting rotational movement of the first movable blade; 
 a second support stud for pivotally supporting rotational movement of the second movable blade independent of the first movable blade; 
 a cutter drive mechanism for driving the first movable blade and the second movable blade to cause a cooperative cutting operation; 
 wherein the cutter drive mechanism includes
 a cutter motor; 
 a gear train including a first gear that is rotationally driven by said cutter motor, and a second gear that is rotationally driven in response to rotation of the first gear; 
 a first eccentric pin that is disposed to an eccentric position on the first gear and engages the first movable blade; and 
 a second eccentric in that is disposed to an eccentric postion on the second gear and engages the second movable blade; 
 
 a first cam formed by the first guide channel and the first eccentric pin for regulating the cutting operation of the first movable blade; and 
 a second cam formed by the second guide channel and the second eccentric pin for regulating the cutting operation of the second movable blade; 
 the printing apparatus further comprising a transportation mechanism for conveying a sheet material that is cut by the paper cutting device; and 
 a printing mechanism that is disposed upstream in the sheet transportation direction from the paper cutting device for printing on the conveyed sheet medium; 
 wherein the first guide channel or the second guide channel has a bend at approximately a middle portion thereof. 
 
     
     
       12. A printing apparatus including a paper cutting device comprising:
 a fixed blade having a cutting edge; 
 a fixed blade frame for supporting the fixed blade; 
 a first movable blade, having a first cutting edge terminating in a first cutting point, and a second movable blade, having a second cutting edge terminating in a second cutting point, disposed for relative movement against the fixed blade with the blade points facing the fixed blade in mutual opposition with the first movable blade and the second movable blade disposed so that the paths of the first cutting point and the second cutting point at least partially overlap during the cutting operation, wherein the first moveable blade and the second moveable blade are configured for movement independent of each other, the first movable blade having a first guide channel and the second movable blade having a second guide channel; 
 a first support stud affixed to a movable blade frame for pivotably supporting rotational movement of the first movable blade; 
 a second support stud affixed to the movable blade frame for pivotally 
 supporting rotational movement of the second movable blade independent of the first movable blade with the first and second movable blades being supported at positions separated from the cutting edge of the fixed blade; 
 a cutter drive mechanism for driving the first movable blade and the second movable blade to cause a cooperative cutting operation; 
 wherein the cutter drive mechanism includes
 a cutter motor; 
 a gear train including a first gear that is rotationally driven by said cutter motor, and a second gear that is rotationally driven in response to rotation of the first gear; 
 a first eccentric pin that is disposed to an eccentric position on the first gear and engages the first movable blade; 
 a second eccentric in that is disposed to an eccentric postion on the second gear and engages the second movable blade; and 
 a transportation mechanism for conveying a sheet material that is cut by the paper cutting device through a sheet transportation path located above the fixed blade; 
 
 a first cam formed by the first guide channel and the first eccentric pin for regulating the cutting operation of the first movable blade; and 
 a second cam formed by the second guide channel and the second eccentric pin for regulating the cutting operation of the second movable blade; 
 the printing apparatus further comprising a printing mechanism that is disposed upstream in the sheet transportation direction from the paper cutting device for printing on the conveyed sheet medium; and 
 an opening and closing cover for opening the sheet transportation path and opening the sheet material storage compartment by moving the fixed blade frame; 
 wherein the first guide channel or the second guide channel has a bend at approximately a middle portion thereof.